[PATCH v4 5/5] ARM: exynos: dts: Add FIMD DT binding Documentation

[Vikas Sajjan]

Hi,

On 19 February 2013 03:16, Sylwester Nawrocki
<sylvester.nawrocki at gmail.com> wrote:
> Hi,
>
>
> On 02/18/2013 11:51 AM, Vikas Sajjan wrote:
>>
>> On 15 February 2013 16:08, Sylwester Nawrocki<s.nawrocki at samsung.com>
>> wrote:
>>>
>>> On 02/15/2013 08:10 AM, Vikas Sajjan wrote:
>>>
>>>> Adds FIMD DT binding documentation both SoC and Board, with an example
>>>>
>>>> Signed-off-by: Vikas Sajjan<vikas.sajjan at linaro.org>
>>>> ---
>>>>   .../devicetree/bindings/drm/exynos/fimd.txt        |   37
>>>> ++++++++++++++++++++
>>>>   1 file changed, 37 insertions(+)
>>>>   create mode 100644
>>>> Documentation/devicetree/bindings/drm/exynos/fimd.txt
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/drm/exynos/fimd.txt
>>>> b/Documentation/devicetree/bindings/drm/exynos/fimd.txt
>>>> new file mode 100644
>>>> index 0000000..bec9d07
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/drm/exynos/fimd.txt
>
>
> Wouldn't Documentation/devicetree/bindings/video/exynos-fimd.txt be more
> appropriate location for this file ? There is also framebuffer driver for
> FIMD. Even if the framebuffer driver gets phased out it still feels like
> a more intuitive location for a display controller bindings.
> This is just my humble suggestion though.
>
I think we can move it there.

> I think you should CC the device tree mailing list and the maintainers.
>
>
will do.

>>>> @@ -0,0 +1,37 @@
>>>> +Device-Tree bindings for fimd driver
>>>> +
>>>> +FIMD stands for Fully Interactive Mobile Display, is the Display
>>>> Controller for
>>>> +the Exynos series of SoCs which transfers the image data from a video
>>>> buffer
>>>> +located in the system memory to an external LCD interface.
>>>> +
>>>> +Required properties:
>>>> +- compatible := value should be "samsung,exynos5-fimd" or
>>>> "samsung,exynos4-fimd"
>>>
>>>
>>> What about older SoCs like S5Pv210 ? There is the FIMD IP block in those
>>> SoCs
>>> as well. There are also differences in the FIMD IP block across various
>>> SoC
>>> version, so either you need to list the quirks in the bindings or use an
>>> appropriate compatible properties if there are significant differences
>>> across
>>> FIMDs that make them not really compatible.
>>>
>> as of now, I was working on Exynos4 and Exynos5 SoC. have to really
>> see the differences in the previous SoC and how to handle all those
>> FIMD IPs in the driver.
>> if you know the differences between these FIMD IPs, please let me know.
>
>
> Please have a look at drivers/video/s3c-fb.c and all driver_data structures
> defined for various SoCs.
>
> [...]
>
I went through the driver_data structures define for s5p64x0,s3c2443,
s5pv210, s5pc100 ad 64xx SoCs.
there are some differences w.r.t number of windows, osd_stride  length
and regsiter offsets.
but  I dont have access to all the above mentioned Boards and so that
I can modify and test on each one of them.

>> we have 3 interrupts and the Interrupt combiner order is FIFO Level ,
>> VSYNC  and LCD_SYSTEM.
>> since we only use VSYNC interrupt , In the driver to get the interrupt
>> number
>>
>> res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
>>           if (!res) {
>>                   dev_err(dev, "irq request failed.\n");
>>                   return -ENXIO;
>>            }
>>
>>   ctx->irq = res->start;
>>
>>   I am passing the 3rd parameter as '0' , to get the VSYNC interrupt,
>> and hence in the DTSI file     i have it in the order  VSYNC,  FIFO
>> LEVEL and LCD_SYSTEM.
>
>
> Yes, I'm aware what's going on here. Since I had to change the interrupts
> order when I used one of the first version of patches adding device tree
> support for FIMD, when I needed working display to test the camera.
>
>
>> what I can do is the pass the 3rd parameter as '1' , and rectify the
>> order in DTSI file as  FIFO LEVEL, VSYNC and LCD_SYSTEM.
>
>
> Then you would have to do it only for dt case. I guess it is okay to
> require VSYNC as the first interrupt. I'm fine with that, as long as
> it is properly documented.
>
 So, I shall keep the logic as is, and just document it well. is it ok.?
> --
>
> Regards,
> Sylwester



-- 
Thanks and Regards
 Vikas Sajjan